A Hypothetic Equation from Which Growth Analysis Equations of Forages and Ruminants are Derived as Special Cases

This study was conducted to suggest a hypothetic equation from which absolute growth rate [AGR] and relative growth rate [RGR] of forages and those of ruminants were derived as special cases. The following equation was suggested: H ₀ = (1/α · dβ/dt) · (α/γ) · (dW/dβ), where α, β and γ are parameters related to AGR of forages [AGRr], AGR of ruminants [AGR_f], RGR of forages [RGR_f] or RGR of ruminants [RGR_r], W denotes dry weight per plant or body weight per animal. Substituting an appropriate term from the four terms (1, A, F and W) for each of α, β and γ gave the following six equations: AGR=dW/dt, RGR=(1/W)·(dW/dt), AGR_f={(1/A)·(dW/dt)}·(A), RGR_f={(1/A)·(dW/dt)}·(A/W), AGR_r=(dF/dt)·(dW/dF), RGR_r={(1/W)·(dF/dt)}·(dW/dF), where A=leaf area, (1/A)·(dW/dt)=net assimilation rate, A/W=leaf area ratio, F=cumulative feed intake, dF/dt=feed ingestion rate, dW/dF=feed efficiency, (1/W)·(dF/dt)=feed ingestion rate per unit W. In this study a hypothetic equation was suggested to the derivation of growth analysis equations of forages and ruminants as special cases.